Yılmaz, Levent
Fickian diffusion of organic penetrants in glassy polymers is formulated as a moving‐boundary problem, and the effect of concentration‐dependent diffusivity on the concentration distribution is investigated. The solutions obtained for concentration‐dependent and constant diffusivity cases are compared. The results show that the concentration distribution curves differ both quantitatively and qualitatively. It is concluded that the sharp advancing boundary between the glassy and rubbery regions is due not only to the discontinuous change in the physical properties of these regions but also to the strong concentration dependency of diffusivity.


Positional effect of nitrogen substitution on a certain perylene chromophore - A semiempirical treatment
Türker, Burhan Lemi; Gumus, Selcuk (Informa UK Limited, 2008-01-01)
The effect of aza substitution at different sites of a benzimidazole derivative of a perylenetetracarboxylic-3,4,9,10 acid is investigated theoretically. These, as yet nonexistent aza derivatives have been subjected to theoretical analysis at PM3 (RHF) type semiempirical calculations. The results indicate that all the structures are stable but endothermic. Substitution of nitrogen on the bay region of the perylene core is more favored. The electronic and vibrational spectra have also been computed.
Studies on the effect of electrode type and substrate temperature on plasma polymerization of two model compounds: Acrylonitrile and hexamethyldisiloxane
Akovalı, Güneri; Dilsiz, Nursel (Wiley, 1990-4)
Polymers were prepared from saturated (HMDS) and unsaturated (AN) monomers in a radio frequency discharge (plasma). The effect of selected parameters such as electrode type (such as Cu, Zn, Ni, Al), reactor type, and substrate temperature (other parameters constant) on chemical structure and the rate of polymer deposition was examined by Fourier transform infrared (FTIR) spectroscopy. Differences in the nature of electrodes and reactor types were found to yield similar plasma products with similar rates of ...
Fused structures in the polymer backbone to investigate the photovoltaic and electrochromic properties of donoracceptor-type conjugated polymers
CEVHER, ŞEVKİ CAN; UNLU, Naime Akbasoglu; OZELCAGLAYAN, Ali Can; APAYDIN, Dogukan Hazar; Udum, Yasemin Arslan; Toppare, Levent Kamil; Çırpan, Ali (Wiley, 2013-05-01)
In this study, two new benzotriazole (BTz) and dithienothiophene (DTT) containing conjugated polymers were synthesized. After successful characterizations of the monomers by proton-nuclear magnetic resonance (1H NMR) and carbon-NMR (13C NMR) techniques, poly(4-(dithieno[3, 2-b:2,3-d]thiophen-2-yl)-2-(2-octyldodecyl)-2H-benzo[d][1,2,3] triazole) P1 and poly(4-(5-(dithieno[3,2-b:2,3-d]thiophen-2-yl)thiophen-2-yl)-2-(2-octyldodecyl)-7-(thiophen-2-yl)-2H-benzo[d][1,2,3]triazole) P2 were synthesized via a typica...
Flow induced polymer-filler interactions: Bound polymer properties and bound polymer-free polymer phase separation and subsequent phase inversion during mixing
Akay, G. (Wiley, 1990-11)
The irreversible absorption of macromolecules on to solid filler particles during mixing in the melt is investigated. The molecular weight and concentration dependence of the absorbed layer thickness are evaluated and the chemical and morphological nature of the irreversibly absorbed polymer (bound polymer) are determined. It is found that the thickness of the bound polymer is not only dependent on the filler concentration but also dependent on polymer molecular weight. Bound polymer in high density polyeth...
On-line preconcentration, speciation and determination of chromium by flame atomic absorption spectrometry(faas) and chemiluminescence
Sürdem, Sedat; Volkan, Mürvet; Department of Chemistry (2004)
Toxicological studies have shown that the degree of toxicity of some elements depends on the chemical form in which the element is present. Chromium (III) is considered as an essential micronutrient for human whereas chromium (VI) is a potentially carcinogenic agent. So the speciation of inorganic chromium in environmental samples is required for accurate assessment of pollution levels. The chromium content in natural water is usually very low, and a preconcentration is often necessary prior to the determin...
Citation Formats
I. TOSUN and L. Yılmaz, “ON THE FICKIAN DIFFUSION OF ORGANIC PENETRANTS IN GLASSY-POLYMERS,” POLYMER ENGINEERING AND SCIENCE, pp. 1043–1045, 1982, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39606.